/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/*
 * This file is based on code from the Apache Harmony Project.
 * http://svn.apache.org/repos/asf/harmony/enhanced/classlib/trunk/modules/luni/src/main/java/java/util/Observer.java
 */

package java.util;

/**
 * Observer must be implemented by objects which are added to an Observable.
 */
public interface Observer {

    /**
     * When the specified observable object's <code>notifyObservers</code>
     * method is called and the observable object has changed, this method is
     * called.
     * 
     * @param observable
     *            the observable object
     * @param data
     *            the data passed to <code>notifyObservers</code>
     */
    void update(Observable observable, Object data);
}